The objective of this study is to document and report the after-effects of encephalitis in the newborn due to transplacentally transmitted Western encephalitis (WE) virus. A secondary objective is to study the effects on the central nervous system of WE virus infection if it occurs in th fetus earlier in pregnancy. Considerable data necessary for this study have already been collected but the results have not been reported by the investigators. The investigators propose to bring the information up to data by (1) identifying any additional cases in infatnts with a fetal We infection through reports of cases in newborns or through reports of pregnancies in women who are known to have had the infection and (2) examining all children who can be located who have had fetal infections with the WE virus.